Figure 8: ROS triggers amastigote differentiation in L. donovani.

. Mid-log-phase L. donovani promastigotes were resuspended at a concentration of 5×10⁶ cells/mL and treated with either just the carrier (water or DMSO), 200 μM H₂O₂ or 5μM menadione. Figures (A) and (B) represent live cell counts determined with the FDA assay using a hemocytometer or H₂O₂ and menadione treatments respectively. Figures (C) and (D) represent an enumeration of flagellated (white columns) and non-flagellated cells (dark columns) for H₂O₂ and menadione treatments. Data in A-D represent the mean of three independent biological replicates (n=3). Error bars represent the standard error of measurement. Student’s two-tailed T-test was used in all panels. P values are indicated in the figure.. (E) Representative images showing the morphology (DIC) and viability (FDA fluorescence) of parasites in regular promastigote culture and cultures treated with 200 μM or 5μM menadione. Bar =14 μM. Viable amastigote-like parasites are indicated by arrows. (F) Scanning electron micrographs depicting morphology of representative cells in regular media or treated with H₂O₂ or menadione. Bar = 3 μM.